The present invention relates to forming bent optical fibers, and optical fiber bends and elbows created thereby, so as to reduce static strain thereat, and hence is an improvement over the invention disclosed in copending Ser. No. 899,363 filed 22 Aug. 1986 (now abandoned), assigned to the assignee of the invention, the disclosure of which is incorporated herein by reference.
Optical fiber has recently been recognized as providing significant advantages over electrical conductors for information transfer. Accordingly, optical fiber has been extensively deployed through a variety of environments where information transfer is desired. In deploying optical fiber, it is often necessary that the fiber be bent, and a minimum bend radius about which the optical fiber can be bent is typically limited by static fatigue which causes the fiber to fracture in time. The minimum bend radius (R.sub.min) for any given fiber is typically limited by a radius (r) of the fiber and a fiber proof test strain level (.epsilon.), and is typically determined as follows: EQU R.sub.min =3r/.epsilon.
where the factor of three comes from long-term static fatigue considerations. For typical optical fiber diameters of 125 microns, 140 microns, and 250 microns, respectively, R.sub.min is 1.87 cm, 2.1 cm and 3.75 cm. respectively, when .epsilon. equals 1.0% which corresponds to a 100 kpsi proof test stress. Such values for the minimum bend radius are often too large for practical applications, and consequently limit the use of optical fiber for high density interconnect systems and other applications where space is a premium and hence small fiber bend radii are required.